Doubly-tuned wireless receiver



Sept. 9, 1924. 1,507,725

J. BETHENOD- ET AL DOUBLY TUNED WIRELESS I RECEIVER Filed Aug. 19. 1921y MAmus LATOUR v Josfpu BHHENUD Patented Sept. 9, 1924.

UNITED STATES JOSEPH BETHNOD AND MARIUS LATOUR, F PARIS, FRANCE.

noUBLY-TUNED WIRELESS Application mea August 19, 1921. serial mi. masso.

To all whom it camera.'

Be `it known that we, JOSEPH Bn'rmiNoD' and MARrUs LATOUR, citizens ofFrance, and residents of Paris, France, have invented certain new anduseful Improvements in Doubly-Tuned Wireless Receivers, of which thefollowing is a specification accompanied v by drawings.

This invention relates jto a receiving arrangement for wirelesstelegraphy and telephony adapted to decrease the inuence of disturbingor-atmospheric currents.

In accordance with this invention, two analogous receiving circuits arebalanced by over and under tuning, i. e. by tuning one to too great awave length and the other to too short a wave length as compared to thesignal. From this it follows' that for continuous waves this balancingconnection becomes essentially a phase connection because of thedetunings in the contrary sense, of the two circuits with respect tothese waves, while for an instantaneous or sudden discharge, thisconstitutes a balancing connection.

The invention is shown in Figure 1.

Fig. 2 shows a modification.

Fig. 1 illustrates an antenna or frame 1 which may be tuned by means ofa capacity to a; wave length to be received.l Prefer.- ably, the circuitof this frame or loop is damped eitherby a series resistance or by aresistance in shunt with the capacity 2. Furthermore, a resistance maybe provided in shunt in a suitable manner that is a .function of thepotential at the terminals of the condenser (detector, valves, etc.) sothat the damping be greater in proportion to vthe value of thispotential. The primary circuit 1-2 controls they secondary receivingcircuits 3, and 5, the secondary capacities 4 and 6 of which areadjusted `in suchfa manner that while one of them is tuned to aV wavelength that is longer than the `wave to be received, the other is tunedto a shorter wave length. From the standpoint of the wave received underthese conditions,I one of the capacities permits the passa-ge of a`current that is in a lagging phase and the other. permits a passage ofacurrent that is in a leading phase.

As a result of this, if 'the inductances are in opposition (from thestandpoint of the mutual induction withthe primary circuit), the twocurrents received will reinforce each other. On the other hand, with asudden discharge, the mutual induction of the two opposed circuits isvery much reduced and,

may even be made equal to zero. f

Y The double coil 7 and the capacity 8 make possible the tuning of theensemble of the secondary system to the length of the wave to bereceived before it actuates the lamp amplifier or detector 9 orgenerally speaking, an amplifier provided with multiple resonances. Itshould be noted that, in each element 3 4, 5-6 of the secondaryreceiving circuit, the atmospheric discharges assume a different wavelength from the re. ceiving. As a whole, Ythe above described permits ofadding to the advantages o'btained through-the diierentiatiom of thedisturbing currents and the currents to be received either by dampingthe antenna or by Adetuning the receiver as disclosed in French Patent502,279 of Marius Latour.

The same reasoning that applies to high frequency applies also tomusical or low frequency. The amplification of the musical currentresulting from'the receiving at a station and responding toa given-tonemay be accomplished in the following manner:

Two receiving circuits are balanced and tuned to the diierent tones, onelower and the other higher than the vtone received.

Two distinct primary receivers may be provided instead of two secondary.receivers, by utilizing two frames or loops. Un-

der certain conditions, these arrangements .may be advantageous. Inaccordance with Figure 2, two frames are used, 1 and 2, beingl situatedin parallelplanes. In accordance with the present invention the mutualinductance of this frame is compensated by an artificial mutualinductance 3. These two frames actuate in an inverse sense throughtheagencyof coils 4 and- 5 a single secondary circuit tuned by means of thecaacity 8 to the wave length to be received.

he two frames 1 and 2 are tuned, one above and the other below, to thewave length to.

be received, i. `e. the fact is taken in consideration that'3 forcontinuous waves of known frequency the currents will add to a. certainphase relation, while for an instantaneous discharger the currents willoppose. The advantages of detuning of the receiving circuit described inFrench Patent Number 502,279 are always retained.

In many cases it will be advantageous tol vary the damping of the highfrequency circuits and this may be done by changmg tenne, tuned to thesignal the values of the nesistanees 10 land 11, as shown in thedrawing, or by other means.

g described our invention, what we claim is: 1. In wireless signallingsystems a circuit tuned to a frequency greater than the signal frequencyan a second circuit tuned to a frequency lower than the signalfrequen'cy, 4and means for opposing the currents in said circuits toprevent response of said stem to sudden discharges. 4

2. wireless alling systems, an antenna tuned to the signal frequency, asecondary circuit connected thereto through only two independentcouplings one coupling being over tuned and the other under tuned inrespect to the signal frequency and a receiver connected to saidsecondary circuit.

3. In wireless signalling systems, an an'- frequency, a secondarycircuit connected only two -ndependent cou lings,` one coup being overtuned andp tun in respect to the signal frequency and thereto throughthe other under mea-ns for varying .the damping of the high frequencycircuits.

In wireless signalling systems, the combination of an antenna circuittuned to signal frequency, a secondary circuit tuned Aas a whole tosignal 'frequency and said secondary circuit comprislng two se aratertions, one tuned to a frequency ower signal reqluency and the othertuned to-a fr uency igher than signal frequen and eac comprising meanscoupled to sai primary circuit. L

5. In wireless signalling systems, the

combination'of an antenna circuit tuned to `signal frequency, asecondary circuit tuned as whole to signal frequency and said secondarycircuit comprising two separate portions, each portion com risinginductance and capacity, one of said rtions being tuned to a frequencybelow signal frequency and the other being tuned to a'frequencyabovesignal frequency and each portion being coupled to said antennacircuit.

' JOSEPH BET'HENOD.

MARIUS LATOUR.

